Auto body components, such as fenders, bumper covers and other body panels, are increasingly fabricated of synthetic organic polymers, such as and particularly thermoplastic polyolefin plastics, sometimes referred to as TPO. Repair of these components requires techniques matched to their unique characteristics. While repair adhesives can be used to finish the repair of damaged areas of the components, the integration of the repaired area with the surrounding panel in a smooth, imperceptible manner requires that the repair material be effectively supported against waviness, protuberances and dishing. By its nature, polyolefin is only difficultly bonded to making support of the repair material problematical.